For structural materials that are intended for high temperature application, it is essential that the material offer some level of inherent oxidation resistance in order to avoid catastrophic failure during use. Nickel based alloys, or superalloys, represent one class of material that is commonly used for high temperature applications, such as turbine components. These nickel based alloys have been found to exhibit good chemical and physical properties under high temperature, stress, and pressure conditions, such as those encountered during turbine operation. However, as larger planes with faster take-off speeds have developed a need has arisen for turbine materials that can withstand greater temperatures.
Multiphase intermetallic materials composed of molybdenum silicides are one alternative to the nickel based superalloys. These multiphase alloys may include either boron or chromium in addition to molybdenum and silicon and have the potential to withstand much higher operating temperatures than the nickel based superalloys. Although the chemical and physical properties of these molybdenum silicide alloys are promising, oxidation of these materials at high temperatures remains a significant problem in their development for use in high temperature applications. At high temperatures (above about 800° C.) these materials naturally form protective oxide coatings that hinder continued oxidation of the underlying material. However, this coating is insufficient to completely halt the oxidation process and over time the reaction of oxygen with molybdenum consumes the alloy.